Lubricant



Patented Aug. 28, 1945 UNITED STATES PATENT OFFICE 2,383,917 p LUBRICANT John D. Morgan, South Orange, N. 5., assignor to Cities Service Oil Company,

a corporation of Pennsylvania No Drawing. Original application July 9, 1942,

New Yfork, N. Y.,

Serial No. 450,287. Divided and this application January 25, 1944, Serial No. 519,649

Claims.

This invention relates to lubricants which are more particularly adaptedfor low temperature lubrication.

Many machines, such as the aeroplane; truck and automobile, operate in atmospheres which may range in temperature from 50 F. to 200? F. A lubricant which is efiective for lubrication in this temperature range should have a comparatively uniform viscosity throughout this temperature range.

The primary object of the present invention is to provide a lubricant and method of lubrication which are efiec'tive in a temperature range of 50 F. to 200 F.

Another object of the invention is to provide a lubricant which is stable and non-corrosive and which is capable of withstanding high bearing pressures. a

With these and other objects in view the invention consists in the lubricant and method of lubricating hereinafter described and particularly defined in the claims.

I have discovered that the alkyl lactates have physical characteristics which adapt them for lubrication in a range of from -50 F. to 200 F. The lactates which are more particularly adapted aslubricants are the alkyl lactates which are esters oi a-hydroxypropionic acid or lactic acid.

The alkyl lactates, particularly adapted for lu-' bricants, have the following physical properties:

Boiling Flash Melting point point point Ethyl lactate Bu tyl lactate Isobutyl lactate These alkyl lactates are oily liquids and have the following viscosities:

'lempera- Viscosities in ture centistokes Ethyl lactate l Buty1lactste.... f I Isobutyl lactate Froman observation of these viscosities it will be seen that all of these lactates have apparently uniform viscosity throughout the ranee'of -40 F. to 200 F.

5 pressure carrying grease.

1 All of the alkyl lactates above mentioned have ood lubricating values, that is they have better lubricating values than the regular petroleum lubricating spindle oil having a viscosity of-200 at F. If 3.2%, for example, of ethyl lactate is added to the spindle oil, the load-carrying capac-- ity of the oil will be increased 20%.

By adding one of the well known extreme pressure addition agents to any of these alkyl lactates the load-carrying capacity of the lactate will be raised to a point where it will carry very high bearing pressures. For example with an extreme pressure 4-ball testing machine ethyl lactate would seize at 450 lbs. pressure. By the addition of 1% of Polane, the ester would not seize at 1000 lbs. pressure. It has been found that if 1% of Polane 0r tricresyl phosphite, or Santolube #261 is added to any of the alkyl lactates the loadcarrying capacity would be raised to the point where they would not seize in the e-ball testing machine at a pressure of 1000 lbs.

The ethyl and butyl lactates are well adapted for the manufacture of greases. These lactates with approximately 6% of sodium soap will form greases that are stable and will not bleed. Preferably the lactate contains 1% of the extreme pressure additive to make the grease an extreme The soap preferably is sodium stearate, although it has been found that sodium oleate or sodium palmitate, or any of the sodium soaps of the fatty acids are adapted for making greases with the ethyl and butyl lactates.

These lactates are neutral and non-corrosive in the metal bearings in which they have been employed and will eflfectively adhere to the bearings through the ,temperature range of -40 F. to 200 F. I

Most of the commonly used extreme pressure addition agents are soluble in the lactates ..".d impart load-carrying capacities to the lactates.

Polane is a product sold by the Patent Chemicals Company and is understood to be an ester of a fatty acid or a chlorinated ester of a Fatty acid, such as ethyl laurate or chlormethyl stearate. Santolube #261 is manufactured by Monsanto Chemical Company and defined as a metallic derivative of an alkylated carboxylic acid containins compounds of tin and sulfur. The tricresyl phosphite referred to above is described in the patent to Engelke No. 2,260,303 granted October 28, 1941 and is described as a tricresyl phosphite, or a mixture of tricresyl phosphite and tricresyl phosphate. The above addition agents also act as oiliness and anticorrosion agents.

This application is a division of my application Serial No. 450,287 filed July 9, 1942 for "Lu-bricants. The ethyl lactate lubricants are specifically claimed in application Serial No. 450,287.

The preferred form of the invention having been thus described, what is claimed as new is:

1. A lubricant consisting essentially oi butyl lactate with a small amount of an extreme pressure addition agent dissolved therein 2. A lubricant consisting essentially oi butyl lactate with approximately 1% of an extreme pressure addition agent dissolved therein.

3. A lubricant consisting essentially of isobutyl lactate with a small amount of an extreme pressure addition agent dissolved therein.

4. A lubricant consisting essentially of isobutyl lactate with approximately 1% of an extreme pressure addition agent dissolved therein.

5. A lubricant consisting essentially of butyl lactate having approximately 6% of sodium stearate embodied therein.

6. A lubricant comprising butyl lactate 93%, sodium stearate 8%, tricresyl phosphite 1%.

' assaerz 7. A lubricant consisting essentially of a butyl lactate having an extreme pressure agent dissolved therein in sufllcient proportion to impart extreme pressure properties to the lubricant.

8. A lubricant consisting essentially ot-a butyl lactate having a small proportion of a sodium soap embodied therein sufilcient to impart grease characteristicstothe lubricant.

' 9. A lubricant comprising approximately 6% of sodium stearate, the remainder of the lubricant consisting essentially of a butyl lactate.

10. A lubricant comprising approximately 93% of a butyl lactate, approximately 6% of a sodium soap and approximately 1% of an extreme pressure agent.

JOHN D. MORGAN. 

